Oldest Meridional System 



527 



argued in other parts of this report, extensive excavations may have 

 subsequently taken place within its limits. 



The fact that the rocks of Berkshire valley have a less dip than 

 those of the Hoosac range, leads naturally to the inference that they, 

 like the sandstone in the Connecticut valley, were not elevated dur- 

 ing the epoch of the oldest meridional system. Yet their dip b eing 

 considerably greater than that of the sandstone, renders it somewhat 

 doubtful whether the Berkshire rocks were not at least partially ele- 

 vated earlier than the sandstone : and this fact excites a suspicion 

 that there may have been three epochs of elevation in a north and 

 south direction. The graywacke, however, between Berkshire and 

 the Hudson, has a very high easterly dip, sufficiently great to be re- 

 garded as belonging to the oldest meridional system and connected 

 with the Hoosac range. And it is not difficult to conceive how a se- 

 ries of rocks of considerable extent, forming only a part of a system 

 of elevation, may have been tilted up much less than the group gen- 

 erally. So that upon the whole, I am greatly in doubt whether the 

 Berkshire rocks ought to be referred to the oldest or the latest merid- 

 ional system. 



In tracing this oldest meridional system beyond the limits of Mas- 

 sachusetts, it cannot be doubted that all that mountain range from New 

 York to Canada, along the western part of Connecticut, Massachu- 

 setts, and Vermont, called in Massachusetts the Hoosac range, and 

 in Vermont the Green Mountain range, constitutes a part of it. Nor 

 can there be any more doubt, that a large part of that broad range 

 forming the eastern side of the Connecticut valley, and extending from 

 Long Island Sound to Canada, at least as far east as a line drawn 

 from the mouth of Thames river through Worcester valley, belongs 

 to the same system. I mean, that if the middle portions of these two 

 ranges belong to the same epoch of elevation, so must their prolonga- 

 tions north and south. The eastern range embraces the highest land 

 in New England ; including Wachusett, Monadnock, and the White 

 Mountains. Since these ranges, however, have not been particularly 

 described in New Hampshire and Vermont, other systems of eleva- 

 tion may there be connected with that under consideration. But the 

 continuity of these ridges renders it almost certain that the oldest me- 

 ridional system extends from one extremity to the other. 



According to the best maps, the most elevated parts of the two ran- 

 ges that have been described, are arranged on a line bearing a few 

 degrees east of north. My own observations on limited portions of 



